Creation of ultracold Cs2 molecules via two-step photoassociation with Gaussian and chirped pulses

An efficient two-step photoassociation (PA) scheme is used to produce ultracold Cs-2 molecules in the excited electronic state. By using the compression effect of the wavepacket in the ground electronic state induced by the Gaussian pulse L-1, the PA efficiency PL of forming ultracold molecules in the excited electronic state with binding energies greater than 3.0 cm(-1) steered by the pulse L-2 can be efficiently enhanced. The influences of temporal width, electric field amplitude and chirp rate on the PA dynamics are analyzed. Moreover, the total PA efficiency is also estimated when the thermal distribution is taken into account.